Complete Mathematics This page intentionally left blank Complete Mathematics Trevor Johnson and Hugh Neill For UK order enquiries: please contact Bookpoint Ltd, 130 Milton Park, Abingdon, Oxon OX14 4SB. Telephone: +44 (0) 1235 827720. Fax: +44 (0) 1235 400454. Lines are open 09.00–17.00, Monday to Saturday, with a 24-hour message answering service. Details about our titles and how to order are available at www.teachyourself.com For USA order enquiries: please contact McGraw-Hill Customer Services, PO Box 545, Blacklick, OH 43004-0545, USA. Telephone: 1-800-722-4726. Fax: 1-614-755-5645. For Canada order enquiries: please contact McGraw-Hill Ryerson Ltd, 300 Water St, Whitby, Ontario L1N 9B6, Canada. Telephone: 905 430 5000. Fax: 905 430 5020. Long renowned as the authoritative source for self-guided learning – with more than 50 million copies sold worldwide – the Teach Yourself series includes over 500 titles in the fi elds of languages, crafts, hobbies, business, computing and education. British Library Cataloguing in Publication Data: a catalogue record for this title is available from the British Library. Library of Congress Catalog Card Number: on fi le. First published in UK 2001 by Hodder Education, part of Hachette UK, 338 Euston Road, London NW1 3BH. First published in US 2001 by The McGraw-Hill Companies, Inc. This edition published 2010. Previously published as Teach Yourself Mathematics. The Teach Yourself name is a registered trade mark of Hodder Headline. Copyright © 2001, 2003, 2008, 2010 Hugh Neill and Trevor Johnson In UK: All rights reserved. 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Impression number 10 9 8 7 6 5 4 3 2 1 Year 2014 2013 2012 2011 2010 v Contents Contents Personal introduction xi Only got a minute? xii Only got fi ve minutes? xiv Only got ten minutes? xvi 1 Number 1 1.1 Introduction – place value 1 1.2 Arithmetic – the four operations 3 1.3 Order of operations 4 1.4 Problems which use arithmetic 7 1.5 Special numbers 8 1.6 Multiples, factors and primes 10 2 Angles 15 2.1 Introduction 15 2.2 Angles 16 2.3 Measuring and drawing angles 18 2.4 Using angle facts 20 2.5 Parallel lines 22 2.6 Bearings 25 3 Fractions 29 3.1 Introduction 29 3.2 What is a fraction? 29 3.3 Which fraction is bigger? 31 3.4 Simplifying fractions 31 3.5 Improper fractions 33 3.6 Adding and subtracting fractions 34 3.7 Multiplication of fractions 36 3.8 Fractions of quantities 37 3.9 Division of fractions 38 3.10 A number as a fraction of another number 40 4 Two-dimensional shapes 44 4.1 Introduction 44 4.2 Triangles 44 4.3 Constructing triangles 48 vi 4.4 Quadrilaterals 50 4.5 Polygons 52 4.6 Interior and exterior angles 53 4.7 Symmetries of regular polygons 55 4.8 Congruent shapes 55 4.9 Tessellations 57 5 Decimals 63 5.1 Introduction 63 5.2 Place value 64 5.3 Converting decimals to fractions 66 5.4 Converting fractions to decimals 1 67 5.5 Addition and subtraction 68 5.6 Multiplication of decimals 69 5.7 Division of decimals 72 5.8 Converting fractions to decimals 2 74 6 Statistics 1 80 6.1 Introduction 80 6.2 Collection of data 81 6.3 Pictograms 82 6.4 Bar charts 83 6.5 Pie charts 87 6.6 Line graphs 89 6.7 Scatter graphs 93 6.8 Discrete and continuous data 96 6.9 Grouping data 97 7 Directed numbers 104 7.1 Introduction 104 7.2 Ordering directed numbers 105 7.3 Addition and subtraction 106 7.4 Multiplication and division 108 7.5 Using a calculator 111 8 Graphs 1 113 8.1 Coordinates 113 8.2 Straight-line graphs 116 8.3 Lines parallel to the axes 121 9 Measurement 125 9.1 The metric system 125 9.2 Imperial units 127 vii Contents 9.3 Converting between metric and imperial units 129 9.4 Choosing suitable units 130 10 Perimeter and area 134 10.1 Perimeter 134 10.2 Area 136 10.3 Area of a rectangle 138 10.4 Area of a parallelogram 141 10.5 Area of a triangle 141 10.6 Area of a trapezium 144 11 Algebraic expressions 148 11.1 Introduction – what is algebra? 148 11.2 Writing expressions 148 11.3 Simplifying expressions 151 11.4 Evaluating expressions 153 11.5 Squaring 155 11.6 Brackets 155 11.7 Factorizing expressions 158 11.8 Indices 159 11.9 Laws of indices 160 11.10 Simplifying expressions with indices 163 12 Approximation 169 12.1 Introduction 169 12.2 Rounding whole numbers 169 12.3 Rounding with decimals 171 12.4 Signifi cant fi gures 174 12.5 Estimates 176 12.6 Rounding in practical problems 178 12.7 Accuracy of measurements 179 13 Equations 1 182 13.1 Introduction 182 13.2 Finding missing numbers 183 13.3 Solving linear equations 183 13.4 Equations with brackets 188 13.5 Solving problems using equations 189 13.6 Solving inequalities 191 14 Percentages 195 14.1 Introduction 195 14.2 Percentages, decimals, fractions 195 viii 14.3 Percentages of quantities 199 14.4 Increasing and decreasing quantities 201 14.5 One quantity as a percentage of another quantity 202 14.6 Percentage increases 203 14.7 Using multipliers 205 15 Formulae 209 15.1 What is a formula? 209 15.2 Evaluating terms other than the subject 211 15.3 Changing the subject of a formula 213 16 Circles 216 16.1 Introduction 216 16.2 Circumference of a circle 218 16.3 Area of a circle 221 16.4 Two properties of circles 224 17 Probability 229 17.1 Introduction 229 17.2 Relative frequency 230 17.3 Probability of a single event 231 17.4 Two events 234 17.5 Tree diagrams 239 17.6 Expected frequency 243 18 Three-dimensional shapes 246 18.1 Introduction 246 18.2 Nets and surface area 249 18.3 Volume of a cuboid 251 18.4 Volume of a prism 253 18.5 Weight of a prism 256 19 Ratio and proportion 260 19.1 What is a ratio? 260 19.2 Scales 262 19.3 Using ratio 265 19.4 Direct proportion 267 19.5 Inverse proportion 269 20 Pythagoras’ theorem and trigonometry 273 20.1 Pythagoras’ theorem 273 20.2 Using Pythagoras’ theorem 274 20.3 Proof of Pythagoras’ theorem 278 20.4 Pythagoras’ theorem problems 279 ix Contents 20.5 Trigonometry 280 20.6 The tangent ratio 281 20.7 Values of the tangent 282 20.8 Using tangents 283 20.9 Sine and cosine 285 21 Indices and standard form 292 21.1 Indices 292 21.2 Laws of indices 293 21.3 Prime factors 294 21.4 Highest common factor 295 21.5 Lowest common multiple 297 21.6 Standard form – large numbers 298 21.7 Standard form – small numbers 301 21.8 Standard form calculations 302 22 Statistics 2 306 22.1 Averages 306 22.2 The mode 306 22.3 The median 307 22.4 The mean 309 22.5 The range 312 22.6 Frequency tables 313 22.7 Grouped frequency tables 315 23 Graphs 2 322 23.1 Equations of straight lines 322 23.2 Drawing straight-line graphs 325 23.3 The gradient of a straight line 328 23.4 Curved graphs 331 24 Equations 2 337 24.1 Simultaneous equations 337 24.2 Algebraic methods 339 24.3 Quadratic expressions 343 24.4 Factorizing quadratic expressions 345 24.5 Quadratic equations 348 24.6 Solution by factorizing 349 24.7 Cubic equations 352 Answers 358 Taking it further 388 Index 393 x Credits Front cover: © Digifoto Silver/Alamy Back cover: © Jakub Semeniuk/iStockphoto.com, © Royalty- Free/Corbis, © agencyby/iStockphoto.com, © Andy Cook/ iStockphoto.com, © Christopher Ewing/iStockphoto.com, © zebicho – Fotolia.com, © Geoffrey Holman/iStockphoto.com, © Photodisc/Getty Images, © James C. Pruitt/iStockphoto.com, © Mohamed Saber – Fotolia.com xi Personal introduction Welcome to Complete Mathematics! Complete Mathematics aims to give you a broad mathematical experience and a fi rm foundation for further study. The book will also be a useful source of reference for homework or revision for students who are studying a mathematics course. This book is primarily aimed at students who do not have teacher support. Consequently, the explanations are detailed and there are numerous worked examples. Throughout this new edition are author insight boxes which provide additional support, including memory aids and tips on how to avoid common pitfalls. Also new to this book are end of chapter summaries of all the key points and formulae. Access to a calculator has been assumed throughout the book. Generally, a basic calculator is adequate but, for Chapters 20 and 21, a scientifi c calculator, that is, a calculator which includes the trigonometric functions of sine, cosine and tangent, is essential. Very little else, other than some knowledge of basic arithmetic, has been assumed. To derive maximum benefi t from Complete Mathematics, work through and don’t just read through the book. This applies not only to the exercises but also to the examples. Doing this will help your mathematical confi dence grow. The authors would like to thank the staff of Hodder Education for the valuable advice they have given. Trevor Johnson, Hugh Neill, 2010 xii Only got a minute? Mathematics is probably the most versatile subject there is. It has applications in a wide range of other subjects from science and geography through to art. In science, without mathematics there would be no formulae or equations describing the laws of physics which have enabled the technology that we use each day to develop. Mathematics enables psychologists to fi nd out more about human behaviour, looking for correlations between sets of statistics. Doctors and pharmaceutical companies use mathematics to interpret the data resulting from a drug trial. An understanding of mathematics is essential in architecture and engineering. Mathematics is also used to model situations such as the stock market or the fl ow of traffi c on motorways. As well as being a useful subject, mathematics is also intrinsically beautiful. Many famous artists like Kandinsky and Escher used mathematics as a basis for their work – Kandinsky made extensive use of geometry Only got a minute? xiii in his paintings and Escher is famed for his complicated tessellations and optical illusions. Mathematics also occurs naturally – in nature there are many examples of mathematical patterns and symmetry. For example, the patterns on the wings of a butterfl y or moth are symmetrical, and the pattern of seeds on a sunfl ower head, the scales of a pinecone and the spiral of a snail’s shell all follow the same sequence of numbers – called the Fibonacci sequence. Maths really is ubiquitous and having an understanding of the basics of mathematics is invaluable to many – arguably all – aspects of modern life. xiv 5 Only got fi ve minutes? The word ‘mathematics’ originally comes from the Greek for knowledge and science. To most people maths means arithmetic – addition, subtraction, multiplication and division – which are the building blocks for maths. Without these we couldn’t interpret large sets of data, solve an equation or work out the area of a shape. We live in a technological age and mathematics underpins all of this technology – without mathematics none of the luxuries of modern life that we all take for granted would be possible. It is hard to think of an aspect of modern life that is not reliant in some way on technology and therefore mathematics. Mathematics is also intrinsic to many careers: civil engineers rely on mathematics to work out whether the bridge they are building will actually support a given load and surveyors use trigonometry to calculate the distance between two points. Also, insurance companies use complex probability tables for their life assurance policies, the self-employed will need to use percentages to fi le their tax returns, while pharmacists use formulae to work out the correct dosage for a particular drug and sportspeople are constantly using forms of intuitive mathematics. Many people lack confi dence in mathematics and feel that they are not very good in this subject. For some reason it seems acceptable to say, ‘Oh, I’m hopeless at maths’, in a way that would not be accepted about reading or writing. This lack of confi dence is often rooted in negative experiences when at school – not ‘getting’ a diffi cult concept, new idea or solution to a problem. However, without realising it, every day we are using maths. Working out which box of cereal is best value for money involves proportion. Placing a bet on a horse requires an understanding of probability. Calculating the best mobile phone tariff involves using simple formulae. Working out how much tax you should pay for your